<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #boxA {
            background-color: blue;
            padding: 5px;
        }
        #boxB {
            background-color: green;
            padding: 5px;
        }
    </style>
</head>
<body>
<div id="boxA">
    <img src="images/2.2.a.jpg">
</div>
<input type="button" value="复制" onclick="doMove()">
<div id="boxB">

</div>
<script>
    function doMove() {
        var boxA = document.getElementById('boxA');
        var boxB = document.getElementById('boxB');
        var img = boxA.firstElementChild.cloneNode();
        if (img)
            boxB.appendChild(img);
    }

</script>
</body>
</html>